Vegetation canopy affects the hydrological and biogeochemical processes of vegetation and soil. When the precipitation went through vegetation canopy, the precipitation is redistributed 3 parts: the canopy interception, stemflow and throughfall. The ratio of the three relates to the structure of canopy, the feature of rainfall and the weather conditions. This research analyzes the stemflow, throughfall pH, rainfall pH and soil profile pH, discusses the effect of the stemflow and throughfall to the soil pH, and explains the effect of the construction of artificial vegetation to the soil pH. 

Scientists from CAREERI (Cold and Arid Regions Environmental and Engineering Research Institute) measured the pH of gross rainfall, stemflow and throughfall, and the pH of soils that are adjacent to the shrub base, beneath the canopy and in the intershrub spaces of two dominant desert shrubs (Caragana korshinskii and Artemisia ordosica), respectively, in the revegetation area established in 1989 of Shapotou area, at the southeastern edge of the Tengger Desert. The study aimed to examine the effects of rainfall redistribution induced by xerophytic vegetation on soil pH variations. Significant differences (p＜0.05) in pH were found between stemflow, throughfall and gross rainfall, with the highest in the gross rainfall, followed by throughfall and stemflow. Soil pH in the intershrub spaces was the highest, followed by that beneath shrub canopy and that adjacent to the shrub base. Soil pH in the 0-10 cm soil profile generally had a lower value than in 10-20 cm soil profile. Soil acidification induced by stemflow of C. korshinskii was more intense than that of A. ordosica. Stemflow and throughfall acidification is considered as an important factor resulting in the decrease of soil pH in the direction from the inthershrub spaces to the shrub base.  

The full text can be seen:http://zgsm.westgis.ac.cn/CN/abstract/abstract2540.shtml